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3 years ago

What are some reasons the human population increased greatly in the past couple hundred years?

Chemistry

1 answer:

Lana71 [14]3 years ago

7 0

Answer:

Explanation:

This rapid growth increase was mainly caused by a decreasing death rate, and particularly an increase in average human age. By 2000 the population counted 6 billion heads, however, population growth started to decline after 1965 because of decreasing birth rates.

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Why do covalent bonds form between elements with similar electronegativity?

sesenic [268]

A COVALENT BOND, FORMS BETWEEN ELEMENTS WITH SIMILAR ELECTRONEGATIVITY AS SHARING OF ELECTRON PAIRS BETWEEN ATOMS IS EASIER AS THEY ARE IDENTICAL.

Explanation:

Bonding atoms with similar electronegativity values form covalent bonds.

A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.

Covalent bonds form between two nonmetal atoms with identical or relatively close electronegativity values

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons, also it is the strength an atom has to attract a bonding pair of electrons to itself.

Pure covalent bonds result when two atoms of the same electronegativity bond. This occurs only when two atoms of the same element bond with each other.

6 0

2 years ago

Read 2 more answers

The following reaction shows the products when sulfuric acid and aluminum hydroxide react.

Elden [556K]

The correct answer is approximately 11.73 grams of sulfuric acid.

The theoretical yield of water from Al(OH)3 is lower than that of H₂SO₄. As a consequence, Al(OH)3 is the limiting reactant, H₂SO₄ is in excess.

The balanced equation is:

2Al(OH)₃ + 3H₂SO₄ ⇒ Al₂(SO₄)₃ + 6H₂O

Each mole of Al(OH)3 corresponds to 3/2 moles of H₂SO₄. The molecular mass of Al(OH)3 is 78.003 g/mol. There are 15/78.003 = 0.19230 moles of Al(OH)3 in the five grams of Al(OH)3 available. Al(OH)3 is in limiting, which means that all 0.19230 moles will be consumed. Accordingly, 0.19230 × 3/2 = 0.28845 moles of H₂SO₄ will be consumed.

The molar mass of H₂SO₄ is 98.706 g/mol. The mass of 0.28845 moles of H₂SO₄ is 0.28845 × 98.706 = 28.289 g

40 grams of sulfuric acid is available, out of which 28.289 grams is consumed. The remaining 40-28.289 = 11.711 g is in excess, which is closest to the first option, that is, 11.73 grams of H₂SO₄.

6 0

3 years ago

What kind of charge would the hydrogen atoms have compared to the oxygen atom in the water molecule? Note: A water molecule 2 hy

Basile [38]

Since water molecules are polar. Unequal sharing of electrons between the elements that make it. The hydrogen atoms would experience a slight partial positive charge as the electron density is more close to the oxygen atom making it partially negative.

3 0

2 years ago

Read 2 more answers

A sample of oxygen gas is compressed from 30.6 L to 1.8 L at constant temperature pressure of 1.8 atm. Calculate the amount of e

ad-work [718]

Answer:

the change in the internal energy of the system is 3,752.67 J

Explanation:

Given;

initial volume of the gas, V₁ = 30.6 L

final volume of the gas, V₂ = 1.8 L

constant pressure of the gas, P = 1.8 atm

Energy released by the system, Q = 1.5 kJ = 1,500 J

Apply pressure-volume work equation, to determine the work done on the gas;

w = -PΔV

w = -P(V₂ - V₁)

w = - 1.8 atm(1.8 L - 30.6 L)

w = 51.84 L.atm

w = 51.84 L.atm x 101.325 J/L.atm

w = 5,252.67 J

The change in the internal energy of the system is calculated as;

ΔU = Q + w

Since the heat is given out, Q = - 1,500 J

ΔU = -1,500 J + 5,252.67 J

ΔU = 3,752.67 J

Therefore, the change in the internal energy of the system is 3,752.67 J

3 0

2 years ago

what is the molecular formula of a compound that contains 38% c, 45% n and 16% h if 0.157 g of the compound occupies 125 ml with

EastWind [94]

The molecular formula of the given compound is CH₅N.

<h3>What is the ideal gas equation?</h3>

The ideal gas law has defined the product of the volume and pressure as equal to the product of the gas constant (R) and absolute temperature of the gas.

The mathematical equation of the ideal gas law is as follows:

PV = nRT

The temperature of the compound, T = 22° C = 295 K

The pressure of the compound, P = 99.5 KPa = 0.982 atm

The volume of the compound, V = 125 ml = 0.125 L

0.125 × 0.982 = (0.157 g/M) × 0.082 ×295

M = 31 g/mol

A number of moles of C = 0.157 ×0.37/12 = 0.00484

A number of moles of N = 0.157 ×0.45/14 = 0.00504

A number of moles of H = 0.157 ×0.16/1 = 0.0251

The simplest ratio of C: N: H is 1 : 1 : 5

The empirical formula of the given compound is CH₅N.

The molecular formula of the compound is CH₅N as the molecular mass is equal to 31 g/mol.

Learn more about ideal gas equation, here:

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4 0

9 months ago